Plant Breeding Methods (CS, HS 541)

Exercise 5 – Genetic Control of Pollen

Give complete answers, but be brief and specific. Show your work.

20 points total

1. Show the genotypes and phenotypes for two inbred cucumber parents and the hybrid produced by crossing the two. Set it up so that the hybrid will be monoecious to assure a long harvest season for the grower. Show how you would reproduce the parental inbreds each year.


2. Show the genotypes and phenotypes for a self-perpetuating population of gynodioecious cucumber.


3. Give the genotypes of the progeny (if any) for the following crosses given a homomorphic gametophytic self-incompatibility system of multiple alleles at the S locus controlling pollen flow in the population.

a. S2S7 x S7S2 –>

b. S3S10 x S10S5 –>

c. S12S12S4S4 x S4S4S12S12 –>

d. S6S5 x S9S3 –>


4. Describe 4 methods that could be used to try to convert temporarily a self-incompatible plant to self-compatible so you could self-pollinate it before it dies (it has a 4-month life cycle).


5. Describe the development of a cytoplasmic-genic hybrid production system for onion, including the development of the male-sterile female parent, the elite male parent, and the maintainer inbred. Show genotypes and phenotypes of the inbreds involved.